For those unfamiliar with the topic, accumulation of senescent (old, damaged, no longer replicating) cells in our tissues and organs is one of the reasons why our organs lose their functionality and why we age. Not only those old cells malfunction, they also secret pro-inflammatory signals (Jian-Lin Res, 2009) and produce toxic substances into the extra-cellular environment, thus leading to many age-related diseases. Moreover, they translate the senescent phenotype to the neighboring cells suggesting to them to assume the same senescent expression.
When we are young, our immune system promptly eliminates the senescent cells. As we grow older, this house-cleaning process slows down.
Elimination of the senescent cells, along (ideally) with periodic activation of telomerase (telomere lengthening enzyme/process), is one of very promising anti-aging strategies. I will cover that approach in detail in one of later posts.
A senolytic is a compound or a drug or a supplement that selectively kills senescent cells leaving healthy young cells unaffected.
Fisetin is a flavonoid, a polyphenol found in small concentrations in fruits and vegetables such as strawberry, apple, persimmon, grape, onion, and cucumber. See the fisetin content in food at the end of the post.
Fisetin is close in structure to quercetin, but not as well studied.
Besides its senolytic properties, Fisetin has also been long known to be an anti-oxidant and to have anti-inflammatory and anti-cancer properties (Maher P, 2015). In addition, Fisetin is not only neuroprotective like other flavonoids, which stems from their anti-oxidant properties, but it is also neurotrophic (causes growth of new brain cells) (Sagara, 2004).
Studies on mice and human tissues have also identified that fisetin acts as a senolytic.
A recent study (Yousefzadeh M, 2018) looked at 11 promising senolytic compounds, including curcumin and quercitin, and found fisetin to be the most effective.
The main findings and conclusions from the study were:
Dosage. What we know -
Toxicity. How much is safe?
Other relevant studies and information:
What we have no information about
Here is some data on Fisetin in fruit
Fruit/Vegetable Amount µg/g
Lotus Root 5.8
Feel free to comment, especially if you have additional information!